====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ kswapd0/79 is trying to acquire lock: ffff888011709098 (&type->lock_class){+.+.}-{4:4}, at: keyring_clear+0xaf/0x240 security/keys/keyring.c:1658 but task is already holding lock: ffffffff8e0518a0 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat mm/vmscan.c:6975 [inline] ffffffff8e0518a0 (fs_reclaim){+.+.}-{0:0}, at: kswapd+0x92a/0x2820 mm/vmscan.c:7354 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (fs_reclaim){+.+.}-{0:0}: __fs_reclaim_acquire mm/page_alloc.c:4301 [inline] fs_reclaim_acquire+0x72/0x100 mm/page_alloc.c:4315 might_alloc include/linux/sched/mm.h:317 [inline] slab_pre_alloc_hook mm/slub.c:4904 [inline] slab_alloc_node mm/slub.c:5239 [inline] __kmalloc_cache_noprof+0x40/0x700 mm/slub.c:5771 kmalloc_noprof include/linux/slab.h:957 [inline] kzalloc_noprof include/linux/slab.h:1094 [inline] assoc_array_insert+0x92/0x2f90 lib/assoc_array.c:980 __key_link_begin+0xd6/0x1f0 security/keys/keyring.c:1317 __key_create_or_update+0x41a/0xa30 security/keys/key.c:877 key_create_or_update+0x42/0x60 security/keys/key.c:1021 x509_load_certificate_list+0x145/0x280 crypto/asymmetric_keys/x509_loader.c:31 do_one_initcall+0x1f1/0x800 init/main.c:1378 do_initcall_level+0x104/0x190 init/main.c:1440 do_initcalls+0x59/0xa0 init/main.c:1456 kernel_init_freeable+0x2a7/0x3d0 init/main.c:1688 kernel_init+0x1d/0x1d0 init/main.c:1578 ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 -> #0 (&type->lock_class){+.+.}-{4:4}: check_prev_add kernel/locking/lockdep.c:3165 [inline] check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain kernel/locking/lockdep.c:3908 [inline] __lock_acquire+0x15a6/0x2cf0 kernel/locking/lockdep.c:5237 lock_acquire+0x107/0x340 kernel/locking/lockdep.c:5868 down_write+0x96/0x1f0 kernel/locking/rwsem.c:1590 keyring_clear+0xaf/0x240 security/keys/keyring.c:1658 fscrypt_put_master_key+0xca/0x190 fs/crypto/keyring.c:80 put_crypt_info+0x26d/0x310 fs/crypto/keysetup.c:573 fscrypt_put_encryption_info+0xf6/0x140 fs/crypto/keysetup.c:787 ext4_clear_inode+0x170/0x2f0 fs/ext4/super.c:1529 ext4_evict_inode+0x9f6/0xe60 fs/ext4/inode.c:320 evict+0x5f4/0xae0 fs/inode.c:837 __dentry_kill+0x209/0x660 fs/dcache.c:670 shrink_kill+0xa9/0x2c0 fs/dcache.c:1137 shrink_dentry_list+0x2e0/0x5e0 fs/dcache.c:1164 prune_dcache_sb+0x10e/0x180 fs/dcache.c:1246 super_cache_scan+0x369/0x4b0 fs/super.c:222 do_shrink_slab+0x6df/0x10d0 mm/shrinker.c:437 shrink_slab_memcg mm/shrinker.c:550 [inline] shrink_slab+0x7ef/0x10d0 mm/shrinker.c:628 shrink_one+0x2d9/0x720 mm/vmscan.c:4921 shrink_many mm/vmscan.c:4982 [inline] lru_gen_shrink_node mm/vmscan.c:5060 [inline] shrink_node+0x2f7d/0x35b0 mm/vmscan.c:6047 kswapd_shrink_node mm/vmscan.c:6901 [inline] balance_pgdat mm/vmscan.c:7084 [inline] kswapd+0x145a/0x2820 mm/vmscan.c:7354 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(fs_reclaim); lock(&type->lock_class); lock(fs_reclaim); lock(&type->lock_class); *** DEADLOCK *** 2 locks held by kswapd0/79: #0: ffffffff8e0518a0 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat mm/vmscan.c:6975 [inline] #0: ffffffff8e0518a0 (fs_reclaim){+.+.}-{0:0}, at: kswapd+0x92a/0x2820 mm/vmscan.c:7354 #1: ffff888000e2e0e0 (&type->s_umount_key#32){++++}-{4:4}, at: super_trylock_shared fs/super.c:563 [inline] #1: ffff888000e2e0e0 (&type->s_umount_key#32){++++}-{4:4}, at: super_cache_scan+0x91/0x4b0 fs/super.c:197 stack backtrace: CPU: 0 UID: 0 PID: 79 Comm: kswapd0 Not tainted syzkaller #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_circular_bug+0x2e2/0x300 kernel/locking/lockdep.c:2043 check_noncircular+0x12e/0x150 kernel/locking/lockdep.c:2175 check_prev_add kernel/locking/lockdep.c:3165 [inline] check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain kernel/locking/lockdep.c:3908 [inline] __lock_acquire+0x15a6/0x2cf0 kernel/locking/lockdep.c:5237 lock_acquire+0x107/0x340 kernel/locking/lockdep.c:5868 down_write+0x96/0x1f0 kernel/locking/rwsem.c:1590 keyring_clear+0xaf/0x240 security/keys/keyring.c:1658 fscrypt_put_master_key+0xca/0x190 fs/crypto/keyring.c:80 put_crypt_info+0x26d/0x310 fs/crypto/keysetup.c:573 fscrypt_put_encryption_info+0xf6/0x140 fs/crypto/keysetup.c:787 ext4_clear_inode+0x170/0x2f0 fs/ext4/super.c:1529 ext4_evict_inode+0x9f6/0xe60 fs/ext4/inode.c:320 evict+0x5f4/0xae0 fs/inode.c:837 __dentry_kill+0x209/0x660 fs/dcache.c:670 shrink_kill+0xa9/0x2c0 fs/dcache.c:1137 shrink_dentry_list+0x2e0/0x5e0 fs/dcache.c:1164 prune_dcache_sb+0x10e/0x180 fs/dcache.c:1246 super_cache_scan+0x369/0x4b0 fs/super.c:222 do_shrink_slab+0x6df/0x10d0 mm/shrinker.c:437 shrink_slab_memcg mm/shrinker.c:550 [inline] shrink_slab+0x7ef/0x10d0 mm/shrinker.c:628 shrink_one+0x2d9/0x720 mm/vmscan.c:4921 shrink_many mm/vmscan.c:4982 [inline] lru_gen_shrink_node mm/vmscan.c:5060 [inline] shrink_node+0x2f7d/0x35b0 mm/vmscan.c:6047 kswapd_shrink_node mm/vmscan.c:6901 [inline] balance_pgdat mm/vmscan.c:7084 [inline] kswapd+0x145a/0x2820 mm/vmscan.c:7354 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246